Moving Hard Drive icon on OS X Desktop?
The key step is to first click the desktop itself. Here's the information from Mac OS X's help file:
Changing the way icons look on the desktop
You can change the size of icons on the desktop. You can also change how they are labeled and how they are arranged.
Click the desktop (the background on your screen), then choose View > Show View Options and make your choices:
Use the "Icon size" slider to make icons larger or smaller.
Adjust the label for items by choosing a size from the "Text size" pop-up menu and selecting a label position.
Select "Snap to grid" to have icons arranged in rows or columns.
Select "Show item info" to see information such as the size of your hard disk or number of items in a folder.
Select "Show icon preview" to have icons appear as a preview of the files' contents.
To organize your icons by name, date, size, or kind, select "Keep arranged by" and choose a way to arrange the icons from the pop-up menu.